1. Field of the Invention
The present invention relates to a provisioning device (PD) connected to a field device, which is an object of provisioning, via a provisioning network separated from a target network, and a method of setting network parameters in the provisioning network.
Priority is claimed on Japanese Patent Application No. 2011-078743, filed Mar. 31, 2011, the contents of which are incorporated herein by reference.
2. Description of the Related Art
All patents, patent applications, patent publications, scientific articles, and the like, which will hereinafter be cited or identified in the present application, will hereby be incorporated by reference in their entirety in order to describe more fully the state of the art to which the present invention pertains.
In an industrial wireless communication standard, a setting process of a PD, which manages setting information of field devices, for a connection to a target network for a field device (device to be provisioned (DBP)) is referred to as provisioning. The provisioning includes over-the-air (OTA) provisioning, which is performed according to a wireless communication protocol actually using communication between the PD and the DBP for control, and out-of-band (OOB) provisioning, which is performed according to a communication protocol other than a communication protocol actually used for control, such as infrared communication or the like.
OTA provisioning includes a method in which the PD on a target network for the DBP installed in a field directly performs provisioning and a method in which a handheld device (hereinafter referred to as a handheld PD) having a PD function provisions the DBP in a network separated from the target network. In the OTA provisioning, a network that performs the provisioning is referred to as a provisioning network, and is used separately from the target network.
FIG. 9 is a diagram illustrating an OTA provisioning process using a handheld PD 101. In the provisioning using the handheld PD 101, network parameters and security parameters (hereinafter collectively referred to as network parameters 102) necessary for a DBP 103 to connect to a target network 200 are set by the handheld PD 101 in a provisioning network 100 separated from the target network 200 are set. Once the setting is completed, the DBP 103 can be connected to the target network 200.
In FIG. 9, a control network 300 such as industrial Ethernet is connected to the target network 200 via a gateway 201. Further, a configurator 301, a distributed control system (DCS) 302, and a management tool 303 are connected to the control network 300.
FIG. 10 is a diagram illustrating the provisioning process. The handheld PD 101 has a function of a routing device, and the handheld PD 101 also periodically transmits a router advertisement to the provisioning network 100 in a broadcast mode as in the routing device (S1). In FIG. 10, the inside of a circle represents a range in which the router advertisement can be received. If the DBP 103 located within a router advertisement zone of the handheld PD 101 receives the router advertisement, the DBP 103 can be connected to the handheld PD 101 by acquiring information about the provisioning network 100 (S2). An actual connection process includes a plurality of transactions.
If the connection to the handheld PD 101 is completed, the handheld PD 101 sets network parameters (DBP setting information 102) for connecting the DBP 103 to a target network (not illustrated) (S3). The actual setting process includes a plurality of transactions. Details of the connection process during the above-described provisioning are disclosed, for example, in “ISA-100.11a-2009 Wireless systems for industrial automation: Process control and related applications, 14 Provisioning, pp. 666 to 693.”
Incidentally, according to a method of setting network parameters in a provisioning network in the related art described above, there is a problem in that the handheld PD 101 does not uniquely select a DBP 103 as an object of provisioning from among all DBPs 103 located within the router advertisement zone of the handheld PD 101 as objects of provisioning. In addition, because all handheld PDs 101, which are transmission sources of router advertisements, are connection candidates, the provisioning may fail if the DBP 103 is connected to an inappropriate handheld PD 101.
Here, although an example in which International Society of Automation (ISA) 100.11a is used as an industrial wireless communication standard has been described, the industrial wireless communication standard is not limited to ISA 100.11a. The same problem occurs in a communication protocol in which the same operation as in ISA 100.11a is performed. Hereinafter, its details will be described.
First, a problem in the provisioning process for a plurality of DBPs 103 and 104 will be described using FIG. 11. Although DBP #1 (103) and DBP #2 (104) are located within a router advertisement zone of the handheld PD 101 in FIG. 11, the handheld PD 101 is assumed to manage setting information of only DBP #1 (103). In ISA 100.11a, DBP #1 (103) and DBP #2 (104) receive the router advertisement together because the handheld PD 101 transmits the router advertisement in a broadcast mode (S1). Subsequently, DBP #1 (103) and DBP #2 (104) receiving the router advertisement are connected to the handheld PD 101 (S2).
If a process of connecting to the handheld PD 101 of DBP #1 (103) and DBP #2 (104) is completed, the handheld PD 101 performs setting of network parameters to DBP #1 (103) and DBP #2 (104). However, in this example, the provisioning for DBP #2 (104) fails even when the provisioning directed to DBP #1 (103) succeeds because the handheld PD 101 manages only the setting information of DBP #1 (103) (S3). That is, there is a problem in that DBP #1 (103) and DBP #2 (104) located within the router advertisement zone are randomly connected to the handheld PD 101, regardless of the provisioning object of the handheld PD 101.
Next, a problem in the provisioning process by a plurality of handheld PDs, that is, handheld PD#1 (101) and handheld PD #2 (201), will be described using FIGS. 12A and 12B. In FIGS. 12A and 12B, handheld PD #1 (101) and handheld PD #2 (201) are located in the neighborhood and the DBP 103 is located in an overlapping portion between provisioning network #1 (100) and provisioning network #2 (200). The setting information of the DBP 103 is assumed to be managed only by handheld PD #1 (101).
As illustrated in FIG. 12A, the provisioning by PD #1 (101) ends in success if the DBP 103 is connected to handheld PD #1 (101). As illustrated in FIG. 12B, the provisioning ends in failure because handheld PD #2 (201) does not manage the setting information of the DBP 103 if the DBP 103 is connected to handheld PD #2 (201). According to ISA 100.11a, a handheld PD selection method relies upon implementation without being defined. Therefore, the DBP is likely to search for a handheld PD by trial and error according to implementation of the DBP, and the certainty that the DBP selects an optimum handheld PD is not ensured.